The differences between the composition of fluorapatite and its monazite-(Ce) and xenotime-(Y) microinclusions from the Volta Grande mine and those crystallised from granitic melts (Förster Reference Förster 1998a, Reference Förster b; Sha and Chappel, Reference Sha and Chappel 1999; Cao et al., Reference Cao, Zhou, Qin, Tang …

Xenotime (YPO 4) is less commonly observed than monazite, which in part may be due to a bulk rock composition in which it is not stable but may also reflect a …

Xenotime, a phosphate ore, is one of the valuable mineral deposits of rare earths similar to monazite. The main characteristics of xenotime are listed below: (1) The content of …

high U content of xenotime-(Y) and composition of early florencite-(Ce) potentially support a genetic association between the HREE mineralization and the coeval unconformity-related U deposits of northern Australia. Nevertheless, we also urge for caution in using xenotime-(Y) composition in isolation as an indicator of geological setting.

If monazite and xenotime can be altered by specific fluid compositions during metamorphism, evidence for the alteration as well as the nature of the alteration could provide information on the composition and physical nature of the fluids involved. Since monazite and xenotime are important geological repositories for P, Th, U, REE and Y,

Understanding geologic processes with xenotime: Composition, chronology, and a protocol for electron probe microanalysis. September 2008; Chemical Geology 254(3) ... analyses in well de ...

Xenotime-(Y), Xenotime-(Yb) The traditional name for this species, almost exclusively referring to xenotime-(Y) (the species xenotime-(Yb) is very rare). The X-ray powder …

The composition, lattice parameters, and elastic constants of natural single crystal YPO4 xenotime from Novo Horizonte (Brazil) were determined using EPMA, XRD, and the pulse-echo technique. The composition indicates a 24% substitution of Y sites with other rare-earth elements. The lattice parameters of the studied crystal deviated only …

Paragenesis and composition of xenotime-(Y) and florencite-(Ce) from unconformity-related heavy rare earth element mineralization of northern Western Australia ORIGINAL …

Fluorapatite forms parallel bands of columnar crystals (≤ 3 cm) in massive quartz. Monazite- (Ce) to (Nd) shows a near end-member composition with very small amounts of cheralite and huttonite components. Widespread xenotime-(Y) forms colloform aggregates or irregular aggregates in association with fluorapatite and monazite.

Western Australian mineral sands deposits contain up to 10% heavy minerals, of which 1-3% is monazite. This in turn typically contains 5-7% of radioactive thorium and 0.1-0.3% of uranium, which is barely radioactive. However, if decay products of either are present in the minerals, the radioactivity levels may be significant when the monazite ...

Uranium was always enriched relative to Th in the analyzed xenotime, and the highest Th content (mean of 0.014 a.p.f.u.) was found in the xenotime from the mineralized quartz veins, which had the ...

of xenotime and host rock are similar which, combined with mass-balance calculations, indicate the importance of this mineral in affecting the HREE as well as Y evolution of late-stage granitic melts.

Zircon and xenotime, from two mineralogically and chemically contrasting granite suites occurring in the Krušné Hory/Erzgebirge Mts., display extended compositional variability with respect to abundances of Zr, Hf, REE, Y, P, Th, Ca, Al, Fe and As. According to their geochemical signatures, P-rich (S-type) and P-poor (A-type) granites could be …

In addition, xenotime-(Y) from the same rock samples gave 266 ± 5.2 Ma age (MSWD = 1.4, n = 44), and this corresponds to Permian (Guadalupian) post-magmatic (subsolidus) recrystallization of ...

Xenotime. Xenotime, which is an orthophosphate like monazite, can be processed by either the sulfuric acid process or by caustic fusion. From: Modern Aspects of Rare Earths and …

Composition: Molecular Weight = 240.21 gm Lanthanum 14.46 % La 16.95 % La 2 O 3 Cerium 29. 17 % Ce 34. ... (1995) p.21-26, Crystal chemistry of the monazite and xenotime structures . View Additional jPOWD Structure files for Monazite-(Ce) Physical Properties of Monazite-(Ce) Cleavage: {001} Distinct, {100} Indistinct : Color: Brown, Colorless ...

There are currently only three internationally distributed RMs for xenotime U-Pb geochronology. These are the MG-1 and BS-1 xenotime crystals described by Fletcher et al. (2004), dated at 490 ± 0.3 and 508.9 ± 0.3 Ma, respectively, and the z6413 xenotime of Stern and Rayner (2003), dated at 993.8 ± 0.7 Ma.

The distribution of Th and U in a crystal of pegmatitic xenotime-(Y) (henceforth named xenotime) from Ås II feldspar quarry (Evje, S Norway) has been studied with transmission electron microscopy (TEM) to determine submicron- to nanoscale processes that might have affected U-(Th-)Pb age record. Xenotime contains high Th …

REE-chemical composition of monazite and xenotime. A total of 133 monazite and 210 xenotime grains (Table 1) were analyzed for their REE, U, Th, and Pb concentrations (ESM1), ... De Souza S, Dubé B, McNicoll VJ, Dupuis C, Mercier-Langevin P, Creaser RA, Kjarsgaard IM (2015) Geology, hydrothermal alteration, and genesis of the …

The crystal chemistry and crystal structure of the rare earth element phosphates, monazite-(Ce), Ce(PO 4), and xenotime-(Y), Y(PO 4), as well as the arsenates, gasparite-(Ce), Ce(AsO 4), and chernovite-(Y), Y(AsO 4), from the hydrothermal quartz-bearing fissures, related to pegmatites overprinted by amphibolite facies, cropping …

Typically, the incorporation of actinides in xenotime from these and other granites, as well as from other rocks, is dominated by thorite-coffinite substitutions. However, in some xenotime grains, the U and Th concentrations are largely accounted for by the substitution mechanism 2 (REE,Y) (super 3+) <-->(Th,U) (super 4+) +Ca (super 2+) .

Abstract Xenotime, from a geochemically heterogeneous series of mildly to strongly peraluminous granites of the Erzgebirge, Germany, displays extended compositional variability with respect to abundances of HREE, Y, U, and Th. With few exceptions, the maximum and minimum concentrations for the lanthanides and actinides …

Comparison of chondrite-normalized REE patterns of xenotime (a-d) and host granites (e-g). Within each of the four pairs of diagrams (a-e, b-d, c-f, d-g), xenotime and host rock are identified by ...

Xenotime chemistry is dominated by the the- oretical end-members HREE-PO4 and YPO4 (.90 mol% in total). Typical xenotime grains from the Erzgebirge granites and from other granites worldwide ...

This is consistent with earlier works on stability of xenotime, which demonstrated that dissolutionreprecipitation reactions are induced by alkali-rich fluids supplied by feldspars (Hetherington ...

Monazite is classified as phosphate minerals with a mixture composition of Ce, La, Pr, and Nd. In addition, monazite has a mix of radioactive elements such as thorium (Th) and uranium (U) at around 4–12% (Jordens et al., 2013). Bastnasite is a fluorocarbonate mineral and xenotime is an yttrium phosphate mineral (YPO 4).

Chemical Formula: YPO4 Composition: Molecular Weight = 183.88 gm Yttrium 48.35 % Y 61.40 % Y 2 O 3 Phosphorus 16.84 % P 38.60 % P 2 O 5 Oxygen 34.80 % O ______ ______ 100.00 % 100.00 % = TOTAL OXIDE Empirical Formula: Y (PO 4) Environment: …

Atmospheric Composition. Atmospheric Composition and Structure ... Departamento de Geologia, Escola de Minas, Universidade Federal de Ouro Preto, Campus Universitário Morro do Cruzeiro, Ouro Preto, Brazil ... The xenotime REE patterns are consistent with an origin from hydrothermal quartz veins in the Datas area that cut …

Bulletin de l'Académie royale de Belgique, 3e série, 9-10, 287.; Prinz, W. (1904) Sur la monazite et le xénotime de Nil-St-Vincent. Bulletin de l'Académie royale de Belgique, 3, 313.; ... Iridescent anthophyllite-gedrite from Simiuttat, Nuuk district, southern West Greenland: composition, exsolution, age. Mineralogical Magazinw, 60, 937-947 ...

Ia Composition Chimioue Du Xenotime En Limousin, Massif Central, Frange [PDF] Related documentation. Annexe; A Rapport D'enquête 2 Sommaire; De 1000 Habitants - 87 - 19 Février 2020; ... Laboratoire de Gdolngie, Universitd de Limoges, 123, avenuz Albert TVamas, 87060 Linnges Cedzx, France.

Constraints on the composition of ore fluids and implications for mineralising events at the Cleo gold deposit, Eastern Goldfields Province, Western Australia. Australian Journal of Earth Sciences, 50(1), 19-38. ... (1931) Sur la présence de xénotime et d'autres minéraux contenant des terres rares dans les veines à bastonite de Bastogne ...

Sm. In xenotime-bearing peraluminous granites, the frac-* E-mail: [email protected] tions of Y and total HREE contained in xenotime vary from;30–50% (Bea 1996a). Xenotime rarely has been studied intensively in con-trast to apatite, zircon, and monazite, on which a consid-erable amount of experimental and analytical work has

Monazite [(Ce, La)PO 4 ] and xenotime [YPO 4 ] are often found together in many deposits, wherein, monazite occurs as a major mineral and xenotime presents as a minor mineral (Chelgani et al. 2015 ...

Zircon and xenotime, from two mineralogically and chemically contrasting granite suites occurring in the Krušné Hory/Erzgebirge Mts., display extended compositional variability with respect to abundances of Zr, Hf, REE, Y, P, Th, Ca, Al, Fe and As. According to their geochemical signatures, P-rich (S-type) and P-poor (A-type) granites could be …

Sm. In xenotime-bearing peraluminous granites, the frac-* E-mail: [email protected] tions of Y and total HREE contained in xenotime vary from;30–50% (Bea 1996a). Xenotime rarely has been studied intensively in con-trast to apatite, zircon, and monazite, on which a consid-erable amount of experimental and analytical work has